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Lifespan boost for mice that feel less pain

By Colin Barras

Pain-free mouse?

(Image: Getty)

No pain, lifespan gain? Mice lacking a type of pain receptor live significantly longer than other mice and have a more youthful metabolism. The finding hints at new targets for efforts to improve metabolic health and longevity in humans.

Youthful characteristics

What’s more, mice lacking the TRPV1 receptors retain some youthful features into old age. For instance, older mice without TRPV1 could metabolise oxygen far more efficiently than typical mice of the same age. They also had more pancreatic beta cells – these release insulin, which makes cells absorb glucose from the blood.

Further investigation revealed what was going on. Without the TRPV1 pain receptor, two proteins involved in the production of a neuropeptide called CGRP cannot be activated, says Dillin, so the mice produce less CGRP. As this neuropeptide inhibits insulin release, mice lacking TRPV1 are able to produce more insulin – which has beneficial knock-on effects for their metabolism.

As well as these advantages to lacking TRPV1 there are disadvantages too, says Dillin. For example, being able to sense pain helps animals avoid harmful objects and life-threatening situations. This probably explains why natural selection has retained the pain receptors in mammals.

“Pain is very important for animals living in the wild and probably outweighs the benefits of a youthful metabolism,” he says.

A longer life?

But the results do suggest that reducing levels of TRPV1 or CGRP might be a way to improve our metabolism in old age, and perhaps even boost lifespan.

But he thinks finding ways to apply the discoveries to human health won’t be easy. “Pharmacological antagonists [that block] TRPV1 have failed safety [testing],” Ahern says – people who took the therapy experienced short-lived hyperthermia and were prone to burning themselves because of their impaired heat sensation. “CGRP antagonists, currently being developed for migraine treatment, might be useful,” he says.